Holding mechanism for use with an ophthalmic tracer, and method

ABSTRACT

The present invention relates to an ophthalmic holding mechanism for holding an eyeglass frame. The holding mechanism includes a base, a clamping mechanism configured for releaseably securing a lens mount of an eyeglass frame, and an actuator operatively associated with the clamping mechanism for causing linear and rotational movement thereof. The clamping mechanism is moveably coupled to the base for linear and rotational movement about an axis of rotation relative to the base, wherein the clamping mechanism is rotatable about first and second spaced pivot points. The present invention also relates to a method of tracing a lens mount of an eyeglass frame.

CROSS REFERENCE TO RELATED APPLICATION AND CLAIM TO PRIORITY

This application is based on provisional application Ser. No.60/899,652, filed Feb. 6, 2007, for Andrews et al., the disclosure ofwhich is incorporated herein by reference and to which priority isclaimed.

FIELD OF THE INVENTION

The present invention relates to an ophthalmic holding mechanism forholding an eyeglass frame. The holding mechanism includes a base, aclamping mechanism configured for releaseably securing a lens mount, andan actuator operatively associated with the clamping mechanism forcausing linear and rotational movement thereof. The clamping mechanismis moveably coupled to the base for linear and rotational movement aboutan axis of rotation relative to the base, wherein the clamping mechanismis rotatable about first and second spaced pivot points. The presentinvention also relates to a method of tracing a lens mount.

BACKGROUND OF THE INVENTION

In the eyeglass industry, it is desirable to provide lenses havingdifferent shapes and sizes to accommodate different sizes and shapes ofeyeglass frames. Generally, eyeglass lenses start out as lens blankshaving certain optical properties designed to correct one or moredefects in a patient's vision. The blanks are usually circular and ofsubstantially larger dimension, for example 70 mm in diameter, comparedto the relatively smaller finished lenses assembled into eyeglassframes. Lens blanks are routinely subjected to edge processing in aneffort to adapt them to a selected size and shape of eyeglass frames.

Edge processing can be achieved using any one of several conventionaltechniques. According to one such technique, eyeglass framemanufacturers provide lens patterns that fit within the respective lensmounts of those manufacturers' eyeglass frames. When a patient selects aparticular style and size of frame, a lens blank which has been formedto correct that particular patient's vision defect is placed in anedging apparatus along with the pattern or patterns provided by theframe manufacturer. The edging apparatus then traces the pattern andremoves material from the periphery of the lens blank in accordance withthe pattern.

Conventional pattern-based techniques have certain drawbacks associatedwith them. For example, a relatively large number of patterns must beprovided, storage space is required for such patterns, and difficultiesarise when the patterns become misplaced or when they are misalignedduring tracing. Typically, one or more patterns must be provided foreach different shape and/or size of eyeglass frame. The amount ofstorage space required for such patterns increases as the choices ineyeglass frame sizes and shapes expand. Therefore, while suchconventional techniques may be adequate for some applications, thereremains a need for a more convenient arrangement.

In order to provide a more convenient arrangement, efforts were made toeliminate or reduce the need for patterns by providing a tracingapparatus capable of tracing the lens mounts of eyeglass frames. Theresults of such tracings (i.e. trace data) then were used to provideedging information for use in edging a lens blank.

A conventional tracer typically includes a clamp assembly for clampingthe frames in a fixed position, and an engager having a projectingsurface for tracing the groove of the frames. Trace data is generatedaccording to the position of the engager. The edger processes the edgeof the lens blank to create an edge profile according to the trace data.Therefore, accurately tracing the groove of the frames ensures a properfit of the lens within the frame opening.

Most conventional tracers are generally effective when the lens mountsin the eyeglass frames are substantially planar. However, many tracersencounter problems when tracing frames having a “high wrap”. The term“high wrap” as used herein encompasses shapes that have a curvaturegreater than 6 diopters. Typically, though not necessarily, high wrap isprovided so that the eyeglass frame more closely follows the contour ofthe wearer's face.

In particular, the engager that performs the tracing in manyconventional tracers is generally biased in a radially outward directionto engage a groove in the lens opening or mount of the eyeglass frame.This radially outward biasing remains effective so long as the groove inthe lens mount extends in the same radially outward direction. Eyeglassframes with high wrap, however, tend to have grooves in the high wrapregion which extend obliquely (and which can even approach theperpendicular) with respect to the radially outward direction. As theengager enters the high wrap region and the groove in the framegradually transitions to a more upwardly extending orientation, gravityacts to pull the engager down and out from the groove. The engagertherefore tends to disengage the groove, rendering the trace datainaccurate.

As described more fully in U.S. Pat. No. 6,618,952, the disclosure ofwhich is incorporated herein by reference, a tracer apparatus fortracing frames having a relatively high wrap has been developed. Thetracer disclosed in the '952 patent includes an object engager whichengages and traces the frames, and an actuator which moves the objectengager into contact with and then along the frames. However, the tracerdisclosed in the '952 patent maintains the frames in a fixed positionduring tracing. The tracer apparatus is therefore adapted to account forhigh wrap of the frame.

SUMMARY OF THE INVENTION

The present invention relates to a holding mechanism for holding a lensmount of an eyeglass frame, a lens or a lens pattern for a tracer. Theholding mechanism adjustably positions the frame, lens or lens patternrelative to an object engager of the tracer apparatus, therebyeliminating or minimizing the effects of high wrap during the tracingprocess.

A holding mechanism for holding an eyeglass frame is disclosed. Theholding mechanism includes a base, a clamping mechanism configured forreleaseably securing a lens mount of an eyeglass frame, and an actuatoroperatively associated with the clamping mechanism for causing linearand rotational movement thereof. The clamping mechanism is moveablycoupled to the base for linear and rotational movement about an axis ofrotation relative to the base, wherein the clamping mechanism isrotatable about first and second spaced pivot points. The presentinvention also relates to a method of tracing a lens mount of aneyeglass frame.

A holding mechanism for holding a lens mount of an eyeglass frameaccording to an embodiment of the present invention includes a baseplate having a slot formed therein which defines a cam path. A table isprovided, which has first and second spaced bearings extending outwardlyfrom a first major surface of the table. The bearings are received inand moveable along the cam path so that the table is moveably connectedto the base plate. A clamping mechanism extends outwardly from a secondmajor surface of the table opposite the first major surface. Theclamping mechanism has at least one clamp adapted for releaseablysecuring an eyeglass frame in a fixed position relative to the table. Amotor operatively associated with the table moves the bearings along thecam path in first and second directions.

The present invention also relates to a method of tracing a lens mountof an eyeglass frame. Eyeglass frames are secured proximate a tracerapparatus having an object engager. At least a portion of a first lensmount is traced with the object engager, thereby generating initialtrace data. A delta Z of the first lens mount is calculated based on thegenerated initial trace data. The eyeglass frames are tilted about avertical axis by a first prescribed angle if the delta Z value exceeds apredetermined threshold, wherein the first prescribed angle correspondsto the first delta Z value. The first lens mount is re-traced using thetracer apparatus if the first delta Z value exceeded the predeterminedthreshold, thereby generating secondary trace data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a holding mechanism according to anembodiment of the present invention;

FIG. 2 is a top plan view of the holding mechanism of FIG. 1;

FIG. 3 is a bottom plan view of the holding mechanism of FIG. 1;

FIG. 4 is an elevational view of the holding mechanism of FIG. 1;

FIG. 5 is a perspective view of some components of the holding mechanismof FIG. 1;

FIG. 6 is a top plan view of the components shown in FIG. 5, withportions shown in phantom;

FIG. 7 is another perspective view of the holding mechanism of FIG. 1;

FIG. 8 is perspective view of some components of the holding mechanismof FIG. 1;

FIG. 9 is another top plan view of the holding mechanism of FIG. 1;

FIG. 10 is a top plan view of some components of the holding mechanismof FIG. 1;

FIG. 11 is a bottom plan view of the holding mechanism showing bearingsin a first orientation along a cam path;

FIG. 12 is a bottom plan view of the holding mechanism showing bearingsin a second orientation along the cam path;

FIG. 13 is perspective view of a fixture for holding a lens or a lenspattern;

FIG. 14 is a perspective view of some components of the holdingmechanism showing the fixture of FIG. 13 secured therein; and

FIG. 15 is a flow chart showing an algorithm according to the presentinvention for tracing a lens mount of an eyeglass frame.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A holding mechanism 10 for holding an eyeglass frame F for tracing thecorresponding lens mounts by a tracer apparatus 12 according to anembodiment of the present invention is best shown in FIGS. 1-4, 7, 9, 11and 12. Holding mechanism 10 is configured for holding frame F. However,holding mechanism 10 may also be adapted for holding a lens or a lenspattern, explained in further detail below.

Referring to FIGS. 1-4, holding mechanism 10 includes a base plate 14having a slot 16 formed therein, which defines a cam path. A table 18having first and second spaced bearings 20, 22 is provided. Bearings 20,22 extend outwardly from a first major surface 24 of table 18, as bestshown in FIGS. 3 and 4. Bearings 20, 22 are received in and moveablealong the cam path. In this way, table 18 is moveably connected to baseplate 14.

As best shown in FIGS. 1 and 4, a clamping mechanism 26 extendsoutwardly from a second major surface 28 opposite first major surface 24of table 18. Clamping mechanism 26 is preferably adapted for releaseablysecuring an eyeglass frame F in a fixed position relative to table 18.

Clamping mechanism 26 preferably includes a frame centering device 30adapted to engage and support a nose portion of the eyeglass frame F.Referring to FIGS. 1, 4 and 6, frame centering device 30 may include acylindrical member 32 having a first portion 34 configured for engagingthe nose portion and a second portion 36 spaced therefrom. A supportwall 38 having first and second spaced centering arms 40, 42 extendsupwardly from second major surface 28 of table 18. Cylindrical member 32is pivotably disposed between centering arms 40, 42 on a pin 44 (shownin phantom in FIG. 6) which extends between centering arms 40, 42. Pin44 extends through an associated opening (not shown) in cylindricalmember 32 on an axis substantially perpendicular to the longitudinalaxis of cylindrical member 32. The opening for pin 44 is disposed incylindrical member 32 such that second portion 36 acts as acounterweight. First portion 34 is pivotally biased upwardly and againstthe nose portion when the eyeglass frames F are supported thereon due tothe weight of second portion 36.

Referring to FIGS. 4, 7 and 8, clamping mechanism 26 also preferablyincludes a lower clamp arm 47 which includes first and second spacedlower frame holders 46, 48, which are configured to engage and supportlower edges of corresponding lens mounts M1, M2 of frame F. Lower frameholders 46, 48 are preferably sufficiently spaced such that each frameholder 46, 48 engages the lower edge of lens mounts M1 and M2 of frame Fat a position thereof which accommodates a broad variety of frames ofdifferent sizes. For example, lower frame holders 46, 48 may be spacedfrom each other by between about 65 mm to about 75 mm, more preferablyabout 70 mm. Each of lower frame holders 46, 48 may include two pinsdisposed in a V-shaped configuration.

Clamping mechanism 26 also preferably includes an upper clamp arm 50.Upper clamp arm 50 preferably includes first and second spaced upperframe holders 52, 54, which are configured to engage and retain upperedges of the corresponding lens mounts M1, M2. Each of upper frameholders 52, 54 is preferably aligned with a corresponding one of lowerframe holders 46, 48, so that lens mounts M1, M2 are retained betweenlower and upper frame holders 46, 48 and 52, 54.

Upper clamp arm 50 may be connected to and supported by an upper clampsupport 56. Preferably, upper clamp support 56 is moveably disposed on alinear bearing or other guide mechanism 58, as shown in FIG. 4. Upperclamp support 56 is vertically moveable toward and away from table 18.Lower clamp arm 47 may be connected to and supported by a lower clampsupport 49. Preferably, lower clamp support 49 is movably disposed on alinear bearing or other guide mechanism 58. Lower clamp support 49 isvertically moveable toward and away from table 18. More specifically,the upper clamp support 56 and lower clamp support 49 are moveablydisposed with each other establishing a coordinated motion that isalways centered about a fixed horizontal plane. As such, upper clamp arm50, and thus upper frame holders 52, 54, are moveable toward and awayfrom lower clamp arm 47 and thus lower frame holders 46, 48. in thisway, clamping mechanism 26 can accommodate differently sized and shapedframes F, while always positioning the frame at the same height relativeto tracer apparatus 12. Due to the weight of upper clamp arm 50 andclamp support 56, clamp support 56 is preferably biased downwardly onthe linear bearing or other guide mechanism 58 toward table 18 due togravity. Thus, upper clamp arm 50 and corresponding upper frame holders52, 54 are biased toward lower frame holders 46, 48. It would be readilyunderstood by one skilled in the art, however, that an associatedspring, counterweight, or mechanized device could also be provided inorder to move clamp support 56.

Preferably, upper frame holders 52, 54 exert a sufficient downward forceso that frame F is rigidly secured by clamping mechanism 26. However,the sufficient downward force is also preferably not excessively highsuch that frame F is deflected or distorted when secured therein,particularly when tracing eye wire frames or other relatively flexibleframes. The weight of clamp arm 50 and clamp support 56 may be adjusted,such as by modifying their size or material construction, to provide foran optimal downward force.

When retained in clamping mechanism 26, frame F is disposed adjacenttracer apparatus 12 so that lens mounts M1, M2 may be traced. Tracerapparatuses suitable for the present invention are available fromNational Optronics, Inc. of Charlottesville, Va. As described in detailin the '952 patent, a tracer apparatus may include an object engageradapted to move into contact with and then along an inner groove orbevel of a lens mount M1 or M2 via an associated actuator during thetracing process. Alternatively, a lens or a lens pattern may be traced.Tracer apparatus 12 may be either secured to or proximate base plate 14,and positioned so that the object engager is adjacent table 18 and maytrace the lens mount secured thereto.

Some tracers, such as the tracer disclosed in the '952 patent, mayinclude an object engager that is angularly and pivotably mounted to theactuator by a pivot mechanism. The actuator moves the object engageralong the lens mount independent of a pivot angle of the object engager,which may be advantageous for some frames including a relatively highwrap. Some tracers may also include a rotator adapted to rotate theobject engager along the lens mount, wherein the pivot mechanism isadapted to pivot the object engager away from an axis of rotation of therotator so that the object engager engages the lens mount (or the edgeof the lens or lens pattern). The pivot mechanism is adapted tofacilitate movement of the object engager toward or away from the axisof rotation as the object engager is actuated. Such tracers including apivot mechanism suitable for tracing frames having high wrap may be usedwith the present invention.

However, tracer apparatus 12 need not include a pivot mechanism toaccurately trace frames having high wrap due to moveable table 18, whichmay move frames F relative to the object engager on tracer apparatus 12so that the effects of high wrap during the tracing process areeliminated or minimized.

Referring to FIGS. 1, 2, 4 and 5, holding mechanism 10 may include toothsprocket 60 and an associated motor 62. Tooth sprocket 60 and motor 62are spaced from table 18, but may be disposed adjacent a periphery 202of base plate 14. Motor 62 is preferably secured to base plate 14. Baseplate 14 may include an opening through which a shaft associated withmotor 62 extends. Sprocket 60 is disposed adjacent upper surface 66 ofbase plate 14 and substantially coplanar with table 18, as shown in FIG.4. Motor 62 extends downwardly away from underside 68 of base plate 14.

It should be understood that the specific orientation of motor 62, toothsprocket 60, idler sprocket 212 and timing belt 206 relative to table 18and/or base plate 14 may be modified, particularly if the size andconfiguration of tracer apparatus 12 requires such modification.

Referring to FIGS. 1, 2 and 5-10, sprocket 60 is coupled to table 18 viaa timing belt 206. Timing belt 206 includes a first end 208 securedwithin first groove 74 in table 18, and a second end 210 secured withinsecond groove 78 in table 18, as best shown in FIG. 6. A single idlersprocket 212 is provided, which is spaced from tooth sprocket 60. Idlersprocket 212 is rotatably disposed on an idler shaft 214, and secured tobase plate 14 via an idler sprocket bracket 216. Timing belt 206 islooped around tooth sprocket 60, with a first portion 218 extending fromtooth sprocket 60, around idler sprocket 212 and toward first groove 74.A second portion 220 of timing belt 206 extends from tooth sprocket 60directly to second groove 78, without looping around idler sprocket 212.

As best shown in FIGS. 3, 11 and 12, slot 16 defines a U-shaped cam pathhaving a linear portion 90 having a first end 92 and a second end 94, afirst arcuate portion 96 extends outwardly from first end 92, and asecond arcuate portion 98 extends outwardly from second end 94.Clockwise rotation of tooth sprocket 60 (shown by arrow CW in FIG. 5)pulls first end 208 of timing belt 206, while providing slack to secondend 210, thereby pulling bearings 20, 22 along slot 16 in a firstdirection (shown by arrow D1). In this way, table 18 is moved in firstdirection D1. Counterclockwise rotation of tooth sprocket 60 (shown byarrow CCW in FIG. 5) pulls second end 210 of timing belt 206, whileproviding slack to first end 208, thereby pulling bearings 20, 22 alongslot 16 in a second direction (shown by arrow D2). Table 18 is therebymoved in second direction D2. Tension is maintained on timing belt 206as it moves in clockwise CW and counterclockwise CCW directions.

First and second bearings 20, 22 are sufficiently spaced such that firstbearing 20 is positioned at a midpoint of linear portion 90 of the campath when second bearing 22 has moved to second end 94, as shown in FIG.3. No further linear motion of first bearing 20 in direction D1 occursafter second bearing 22 has reached second end 94. However, as first end208 of timing belt 206 continues to pull table 18, second bearing 22 isforced along second arcuate portion 98 away from second end 94, as shownin FIG. 11. First bearing 20 defines a first pivot point of table 18when disposed at the midpoint of linear portion 90, with second bearing22 proceeding along second arcuate portion 98. Movement of secondbearing 22 along second arcuate portion 98 translates into rotationalmovement of table 18.

Similarly, second bearing 22 is positioned at the midpoint of linearportion 90 of the cam path when first bearing 20 has moved to first end92. No further linear motion of second bearing 22 in direction D2 occursafter first bearing 20 has reached first end 92. As second end 210 oftiming belt 206 continues to pull table 18, first bearing 20 is forcedalong first arcuate portion 96 away from first end 92, as shown in FIG.12. Second bearing 22 defines a second pivot point of table 18 whendisposed at the midpoint of linear portion 90 as first bearing 20proceeds along first arcuate portion 96. Movement of first bearing 20along first arcuate portion 96 translates into rotational movement oftable 18.

Tracer apparatus 12 may include a controller such as a microcomputer forcontrolling trace cycles, a user interface, and a display screen.Preferably, tracer apparatus 12 includes a touch screen user interfacefor acquiring or entering a job number, setting up the trace cycle asdesired, selecting frame type and/or material, and entry of otherinstructional data, as described in the '952 patent. Motor 60, and thusmovement of table 18, is controlled by the controller associated withtracer apparatus 12. When the first trace cycle is initiated, table 18may be biased either in first direction D1 until lens mount M1 ispositioned ‘straight on’ to the object engager of tracer apparatus 12,or in second direction D2 until lens mount M2 is positioned straight onto the object engager depending on the user's selection and processinginstructions, as shown in FIGS. 7 and 9 depending on initial parameters.Lens mount M1 is moved horizontally (left or right) by rotating toothsprocket 60 clockwise CW or counterclockwise CCW, thereby pulling table18 in first or second directions D1, D2 via timing belt 206 and movingbearings 20, 22 along linear portion 90.

Motor 60 may be controlled by the associated controller such that table18 is automatically moved by a predetermined distance based on frameinformation input or selected by the user. Alternatively, associatedcontrols for causing movement of table 18 in directions D1 or D2 may beprovided. In either case, table 18 may be moved by a controlled distanceso that lens mount M1 is positioned ‘straight on’ to tracer apparatus12. In this straight on position, the object engager may be aligned withand start the tracing process at a known position relative to the lensmount M1. For example, the object engager may be aligned with lowerframe holder 46 (or 48 depending on the lens mount being traced) orupper frame holder 52 (or 54). Given frame holder 46, 48, 52, 54 engagelens mounts M1, M2, the position of the lens mount M1, M2 at thesepoints is known. In this way, the object engager properly engages thelens mount M1 or M2 when the tracing process is initiated.

However, the object engager could also be aligned at other positionsrelative to lens mount M1 (or M2), such as the boxing center of the lensmount M1. As known in the art, the ‘boxing center’ is defined as thecenter of the smallest rectangle which encloses the lens mount shapeusing horizontal and vertical lines. The horizontal or A dimension isdefined as the distance between the two vertical sides of the box. Thedistance between the top and bottom of the box is the vertical or Bdimension. The curvature or wrap of lens mount M1, or height Z, is alsodetermined by tracer apparatus 12.

As noted above, tracer apparatus 12 includes an object engager adaptedto move into contact with and then along an inner groove or bevel oflens mount M1 during the tracing process. Tracer apparatus 12 mayinclude rotation and pivot mechanisms to account for the A and the Bdimensions of lens mount M1, as well as Z data. However, because table18 is horizontally moveable as bearings 20, 22 move along linear portion90, tracer apparatus 12 may be stationary with respect to right and leftmovement.

Initial trace data of lens mount M1 is gathered by tracer apparatus 12during the first trace cycle. From this initial trace data, a ΔZ valueof the maximum and minimum A dimension measurements is established. TheΔZ value is used to evaluate if frame tilting via rotation of frame F ontable 18 is needed to accommodate for frame wrap. A threshold ΔZ valuemay be used to determine whether frame titling is needed, which may be adefault threshold or a user definable threshold that is empiricallyestablished based on lab experience.

If the threshold ΔZ value is not exceeded, frame tilting is not requiredto accurately trace lens mount M1. The initial trace data of lens mountM1 is sufficiently accurate. Frame F may then be linearly moved indirection D2 via actuation of motor 60 a controlled or predetermineddistance until the object engager of tracer apparatus 12 is aligned withlens mount M2 (if dual eye trace has been specified by the user). Tracedata of lens mount M2 is then gathered by tracer apparatus 12 during asecond trace cycle. Table 18 may then be returned to its defaultposition on base plate 18, and frame F removed from clamping mechanism26. The gathered trace data may then be dispatched as needed.

If the threshold ΔZ value is exceeded, frame titling is required. Anangle of tilt needed to orthogonalize lens mount M1 to the tracing axisis calculated from the ΔZ value. Predetermined angles of tilt may beprovided which correspond to ΔZ values. For example, the greater the ΔZvalue, the greater the angle of tilt required. Frame F is tilted bymoving second bearing 22 a predetermined distance along second arcuateportion 98 away from second end 94, which corresponds to the calculatedangle of tilt required. Table 18 rotates about the first pivot pointdefined by first bearing 20 disposed at the midpoint of linear portion90 as second bearing 22 moves along second arcuate portion 98 thepredetermined distance.

Once frame F has been rotated to the desired angle of tilt, lens mountM1 is re-traced with a second data gathering trace. Rotation of lensmount M1 eliminates or substantially minimizes the affects of high wrapon the tracing process, given lens mount M1 is orthogonalized to thetracing axis of tracer apparatus 12. The ΔZ measurements required by theobject engager during re-tracing are thereby minimized, preferably tonear zero. In this way, tilting of frame F via rotation of table 18effectively ‘unwraps’ lens mounts having a high wrap.

After lens mount M1 has been re-traced, frame F is linearly moved indirection D2 via actuation of motor 60 a controlled or predetermineddistance until the object engager of tracer apparatus 12 is aligned withlens mount M2 (if dual eye trace has been specified by the user). If itwas determined that lens mount M1 required frame tilting, frame F istilted to the same calculated angle of tilt required for lens mount Ml,but mirrored about a center plane of frame F. The angle of tilt requiredfor lens mount M2 mirrors the angle of tilt required for lens mount M1given the shape and trace values of lens mount M2 are inverse to thoseof lens mount M1. Trace data of lens mount M2 is then gathered by tracerapparatus 12. Table 18 may then be returned to its default position onbase plate 18, and frames F removed from clamping mechanism 26. Thegathered trace data may then be dispatched as needed.

An algorithm for tracing lens mounts M1, M2 of frames F according to apreferred embodiment will now be described with reference to the flowchart of FIG. 15. Preferably, tracer 12 and holding mechanism arecontrollable via a user interface (not shown). A user selects a tracerwrap algorithm at S1. The user may then select or pre-set rotationalangles associated with a level of wrap at S2. These angles of rotationare therefore predetermined prior to tracing, and may be arbitrarily setby the user. The angles of rotation in a first direction correspond topositions of first bearing 20 along first arcuate portion 96, and anglesof rotation in a second direction opposite the first directioncorrespond to positions of second bearing 22 along second arcuate path98. For example, the user may set values of 15, 20 and 25 degreesrotation corresponding to ‘low’, ‘medium’ and ‘high’ tilt angles, whichcorrespond to rotational movement of clamping mechanism 26 relative tothe tracing axis. A pre-set initial table angle may also be set by theuser, for example, an initial tilt angle of 10 degrees. The user alsoselects whether lens mount M1 or lens mount M2 is to be traced, or ifboth lens mounts M1, M2 are to be traced, at S3.

As shown in FIGS. 1, 2 and 4-10, frames F are secured to table 18 viaclamping mechanism 26 in a substantially vertical orientation relativeto base plate 14, with the nose portion of frames F supported bycylindrical member 32 and lens mounts M1, M2 retained between lower andupper frame holders 46, 48, 52, 54. Bearings 20, 22 may be positionedwithin slot 16 at a default position, wherein bearing 20 is disposed atthe midpoint of linear portion 90, as shown in FIG. 3. In this position,table 18 is positioned on base plate 14 so that upper clamp arm 50 is‘straight on’ or orthogonalized to the tracing axis of the objectengager of tracer apparatus 12, as best shown in FIGS. 1,2 and 4.

The user then starts the cycle at S4. If lens mount M1 was selected fortracing, table 18 is linearly moved in direction D1 to a left position(if not already in the left position) at S5 and S6, wherein secondbearing 22 is disposed at second end 94, as shown in FIG. 3. If lensmount M2 was selected for tracing, table 18 is linearly moved indirection D2 to a right position at S5 and S7, wherein first bearing 20is disposed at first end 92.

Clamping mechanism 26, and therefore frames F, are rotated to an initialpre-set angle, if pre-set by the user at S8. A first trace cycle is theninitiated using tracer apparatus 12 at S9, wherein a portion of theselected lens mount M1 (or M2) is traced with the object engagerassociated with the tracer. When tracing lens mount M1 (or M2), thetrace may be initiated at an “initial” tilt angle. Up to about ½ of thecircumference of lens mount M1 (or M2) may be traced to make adetermination as to the most appropriate angle to use to trace theentire frame. For example, between about 80 degrees and about 180degrees of the lens mount may be traced during this initial trace.However, it should be understood that the specific portion that istraced may be arbitrarily set by the user. Initial trace data is therebygenerated during this initial trace. The Z differential during thisinitial trace is evaluated against a predetermined range to determinethe tilt angle, if any, to use.

Specifically, a delta Z is calculated based on the generated initialtrace data at S10, and compared to a predetermined low delta Z threshold(“Low (z)”). Preferably, the delta Z of the lens mount is simultaneouslymeasured as the lens mount is being traced during the first trace cycle.

If the measured delta Z does not exceed the predetermined low delta Zthreshold as the initial trace is proceeding, the object engagercontinues to trace the entire lens mount M1 or M2, and completes thetrace at S11.

However, if the measured delta Z exceeds the predetermined low delta Zthreshold during the initial trace, but does not exceed a predeterminedmedium delta Z threshold (“Medium (z)”) at S12, then the process revertsback to step S8 and the clamping mechanism 26 is rotated a predeterminedangle associated with low wrap (“Low (u)”) at S9. If the measured deltaZ exceeds the predetermined medium delta Z threshold, but does notexceed a predetermined high delta Z threshold (“High (z)”) at S12, thenclamping mechanism 26 is rotated a predetermined angle associated withmedium wrap (“Medium (u)”) at S9. If the measured delta Z exceeds thepredetermined high delta Z threshold (S12), then clamping mechanism 26is rotated a predetermined angle associated with high wrap (“High (u)”)at S9.

The lens mount M1 or M2 is then re-traced at S9 if the predetermineddelta Z threshold was exceeded during the initial trace. Thus, duringthe second trace, one of “Low(u)”, “Medium(u)”, or “High (u)” tiltangles will be used. These values are set by the operator. Thecorresponding angle of tilt of clamping mechanism 26 is automaticallydetermined by the associated software.

After the second trace is complete, the software evaluates the measuredtilt angle of the frame, and if it is outside a predetermined tolerance(settable by the operator), the software causes the frame to be tiltedone more time before tracing lens mount M1 (or M2) a final time. Thisfinal tilting of the frame will essentially eliminate the tilt angle ofthe frame, as interpreted by tracer 12. If necessary, this third traceof the frame will be executed.

Specifically after the second trace, the delta Z is re-measured andcompared to the predetermined low delta Z threshold at S10. Furtheradjustment may be initiated at S12 if the predetermined delta Zthreshold is still exceeded. Once the measured delta Z is less than thepredetermined low delta Z, the object engager completes the trace, andthe frame angle tilt is calculated based on the measured delta Z at S11.

The angle that clamping mechanism 26 was rotated during the precedingtrace is subtracted from the calculated frame angle tilt, and theresulting value compared to a predetermined maximum threshold at S13.

If this resulting value is less than the predetermined maximumthreshold, the process proceeds to S14, wherein it is determined whetherthe other lens mount M1 or M2 is to be traced based on the user'sinstructions at S14. If the other lens mount M1 or M2 is not to betraced, the process is complete at S16.

If the other lens mount M1 or M2 is to be traced, the process revertsback to step S6, wherein clamping mechanism 26 is shifted to a left orright position (depending on the position of the initially traced lensmount M1 or M2). However, the final tilt angle used for the first lensmount traced is preferably the starting tilt angle for tracing thesecond lens mount. In this way, the process is expedited when tracingthe second lens mount.

If the resulting value calculated at S13 still exceeds the predeterminedmaximum threshold, the angle that clamping mechanism 26 was rotatedduring the trace is compared to the calculated frame angle tilt at S15,and the process reverts back to S8 and S9, wherein clamping mechanism 26undergoes further tilt adjustment based on this comparison and the lensmount M1 or M2 is retraced a third time. The process then proceeds tostep S10 as described above.

It should be understood that the algorithm described above and shown inFIG. 15 is exemplary only, and the present invention is not so limited.It would be readily understood that the specific processing steps may bemodified. Further, specifications such as the predetermined anglesassociated with low, medium and high wrap, are predetermined only byuser setup. Therefore, as shown in the flow chart, Initial(u), Low(u),Med(u), Hi(u), and Tolerance(u) may all be set by the user. Similarly,predetermined low, medium and high delta thresholds, as well as thepredetermined threshold calculated at step S13 described above, may bemodified by the user and/or at the time of programming.

As disclosed above, the holding mechanism of the present invention mayalso be configured for securing a lens or a lens pattern during atracing operation. A lens or lens pattern may be attached to a patternor lens holder as described in the '952 patent. For example alignmentpins and magnets may be used to secure a lens pattern to a patternholder, and adhesive pads may be used to secure a lens to a lens holder.The pattern or lens holder may then be secured to holding mechanism 10.

As best shown in FIGS. 13 and 14, a fixture 100 includes a frameconfigured for being releaseably secured by frame holders 46, 48, 52,54. Fixture 100 includes an upper support 104 for being engaged by upperframe holders 52, 54, and lower supports 106, 108 for being engaged bylower frame holders 46, 48, respectively. As shown in FIG. 13, aU-shaped support 110 is provided intermediate lower supports 106, 108,which is configured for extending around centering device 30 andcylindrical member 32 when fixture 100 is retained between frame holders46, 48, 52, 54.

A holder 112 extends outwardly from a strut 114 secured to an end 116 offixture 100, on which a lens pattern P, or a lens, may be secured. Whenfixture 100 is secured by clamping mechanism 26, table 18 may then betilted to a predetermined angle wherein the secured pattern P or lens is‘straight on’ or orthogonalized to the tracing axis of the objectengager of tracer apparatus 12, as shown in FIG. 14. Once in thisposition, lens pattern P or lens may be completely traced without theneed for further rotation of clamping mechanism 26.

It would be readily understood that various other configurations for afixture for holding a lens pattern or lens may be provided, so long asthe fixture secures the lens pattern or lens in a position orthogonal tothe tracing axis of tracer 12. For example, a fixture configured forbeing connected to some other portion of clamping mechanism 26, e.g.upper clamp support 56, or lower clamp support 29, or some other portionholding mechanism 10, may be provided. Trace data is then gathered bytracer apparatus 12, and the lens or lens pattern may then be removedfrom the associated holder.

It will be apparent to one of ordinary skill in the art that variousmodifications and variations can be made in construction orconfiguration of the present invention without departing from the scopeor spirit of the invention. Thus, it is intended that the presentinvention cover all such modifications and variations, and as may beapplied to the central features set forth above.

1. A holding mechanism for holding an eyeglass frame, comprising: abase; a lens mount clamping mechanism for releaseably securing a lensmount of an eyeglass frame, said lens mount clamping mechanism moveablycoupled to said base for linear movement relative to said base and forand rotational movement about an axis of rotation, said lens mountclamping mechanism rotatable about at least one pivot point; and anactuator operatively associated with said lens mount clamping mechanismfor causing said linear and rotational movement thereof.
 2. The holdingmechanism of claim 1, wherein said lens mount clamping mechanismrotatable about first and second spaced pivot points, and wherein saidclamping mechanism is rotatable in a clockwise direction about saidfirst pivot point and rotatable in a counter-clockwise direction aboutsaid second pivot point.
 3. The holding mechanism of claim 1, whereinsaid clamping mechanism includes a first frame holder configured forengaging a first lens mount of the eyeglass frames and a second frameholder configured for engaging a second lens mount of the eyeglassframes.
 4. The holding mechanism of claim 3, wherein said first frameholder is aligned with said axis of rotation when said clampingmechanism is linearly moved to a first position, and said second frameholder is aligned with said axis of rotation when said clampingmechanism is linearly moved to a second position.
 5. The holdingmechanism of claim 1, wherein said clamping mechanism secures theeyeglass frame in a substantially vertical orientation relative to saidbase.
 6. The holding mechanism of claim 2, wherein said first pivotpoint is aligned with said axis of rotation when said clamping mechanismis linearly moved to a first position, and said second pivot point isaligned with said axis of rotation when said clamping mechanism islinearly moved to a second position.
 7. The holding mechanism of claim1, wherein said axis of rotation is substantially perpendicular to adirection of linear movement of said clamping mechanism.
 8. The holdingmechanism of claim 1, wherein movement of said clamping mechanismrelative to said base is defined by movement of associated first andsecond bearings received in and moveable along a cam path.
 9. Theholding mechanism of claim 8, wherein said cam path is U-shaped having alinear portion having first and second ends, a first arcuate portionextending outwardly from said first end, and a second arcuate portionextending outwardly from said second end.
 10. The holding mechanism ofclaim 9, wherein said first bearing defines a first pivot point whendisposed at a central position along said linear portion of said campath, said second bearing disposed in and moveable along said secondarcuate path when said first bearing is disposed at said first pivotpoint, said clamping mechanism rotatable about said axis of rotation assaid second bearing moves along said second arcuate path.
 11. Theholding mechanism of claim 10, wherein said second bearing defines asecond pivot point when disposed at the central position, said firstbearing disposed in and moveable along said first arcuate path when saidsecond bearing is disposed at said second pivot point, said clampingmechanism rotatable about said axis of rotation as said first bearingmoves along said first arcuate path.
 12. The holding mechanism of claim1, further comprising a tracer apparatus proximate said clampingmechanism, said tracer apparatus having an object engager adapted tomove into contact with and then along a lens mount releaseably securedby said clamping mechanism.
 13. The holding mechanism of claim 1,wherein said clamping mechanism includes a frame centering deviceadapted to engage and support a nose portion of the eyeglass frame. 14.The holding mechanism of claim 13, wherein said frame centering deviceis intermediate first and second pivot points of said lens mountclamping mechanism.
 15. The holding mechanism of claim 1, wherein saidclamping mechanism includes a lower clamp arm having first and secondspaced lower frame holders configured to engage a lower edge ofcorresponding first and second lens mounts of the eyeglass frame, and anupper clamp arm having first and second spaced upper frame holdersconfigured to engage an upper edge of the corresponding first and secondlens mounts, the eyeglass frame being retained between said upper andlower frame holders and aligned for engagement by a tracing mechanism.16. The holding mechanism of claim 15, wherein at least one of saidlower and upper frame holders lower frame holders are V-shaped.
 17. Theholding mechanism of claim 15, wherein said lower clamp arm isvertically moveable toward and away from said upper clamp arm.
 18. Theholding mechanism of claim 15, wherein said upper clamp arm isvertically moveable toward and away from said lower clamp arm.
 19. Theholding mechanism of claim 18, wherein said upper clamp arm is biasedtoward said lower clamp arm.
 20. The holding mechanism of claim 1,further comprising a fixture configured for being releaseably secured bysaid clamping mechanism, said fixture including a holder adapted forsecuring one of a lens or a lens pattern. 21-25. (canceled)